Report on methods and classification of stress, inattention - sensation

D1.1.2
Contract N. IST-507231
attention impairment on the performance task may be related to the subject’s use of extra
effort as a compensatory strategy during the performance test. However, the mobilization of
extra effort is a limited compensatory resource that is efficient only on short-term tasks. Thus,
EEG and EOG related signs of sleepiness could give a more correct description of the
subject’s attention level at work than the results of the performance tasks.
6. Recommendations for the measurement of stress,
emotion, and inattention in natural conditions
There are many well-established physiological markers for the measurement of stress and
emotions and the selection of the “best” one will depend on the question of the study.
Heart rate and blood pressure are frequently used markers of acute stress that are feasible and
easy to use in most situations, and permits longitudinal (ambulatory) recordings. The response
is also relatively easy to interpret – increased stress is associated with increased levels.
However, it is important to simultaneously monitor physical activity and body posture and
eliminate their contribution to the results in order to get a “pure” and reliable stress measure.
If HRV analysis will be made one may also need to record respiration for control purpose.
However, the selection of suitable physiological parameters will depend on the question that
should be studied and contextual factors. For example, if the studied group has
musculoskeletal disorders, or the stressor includes repetitive work movement, EMG would be
a feasible marker to record. Although biochemical parameters (stress and anabolic hormones)
are not the scope of SENSATION, they should not be excluded in the study of stress. In
particular, biochemical variables (such as cortisol and testosterone, which can be measured in
saliva) would probably be preferred, rather than autonomic variables, in the study of chronic
stress (Kelly, 2001). In general it is a good strategy to measure several parameters
simultaneously and examine the fluctuations over time. The overall level of a certain
physiological marker does not always discriminate between low and high stress situation,
rather it is the profiles over time that seem to reflect the differences.
This argues for the use of multi-sensorial systems that record several parameters at the same
time. However, even though extraneous factors such activity is controlled for, it is not
possible to draw any conclusions of an individual’s stress state based on only physiological
recordings. As mentioned earlier, the physiological measures of stress and emotional states
indicate the non-specific neurophysiological activation of the body and give no information of
the emotional value. This means that an elevated level may also occur during pleasant and
non-stressful activities. Thus, it is important to get information of the subjective emotional
experiences of the situation. Usually this is obtained through paper and pen instruments,
although recently, hand-held computers have been introduced as recording device for ratings.
We suggest that one should continue along this line and develop measurement systems that
also can record subjective ratings and other behavioral events in connection with
physiological recordings.
One of the simplest ways to measure stress would be to use a wrist monitor (e.g. actigraph or
actiwatch) that records heart rate, wrist activity and with the possibility to make ratings. In
addition, wrist activity can also be used for quantification of sleep length and awakenings.
It is also advantageous to make physiological recordings during sleep. Sleep offers a
relatively standardized recording situation that eliminates most of the influences due to
physical activity and posture. Elevated neurophysiological activation during rest and sleep is
probably one of the best indicators of chronic stress and indicates problems to shut off the
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Karolinska Institutet